Deep eutectic solvents for repairing electrode materials of direct recycling

A repairing solution based on the deep eutectic solvent for repairing the degraded electrode materials with spent cathodes in the direct recycling process of lithium or sodium batteries, comprising:

• hydrogen bond donors;
• hydrogen bond acceptors;
• and
• element replenishment agents;
• wherein the deep eutectic solvent has a eutectic point no higher than 150° C.;
• wherein the deep eutectic solvent is capable of solvation of element replenishment agents of at least 5 wt %;
• wherein the element replenishment agents provide replenishment of metal ions selected from Li, Na, Co, Fe, Ni, Mn, or combinations thereof,
• wherein the deep eutectic solvent has a Li+ ion diffusion coefficient or Na+ diffusion coefficient lower than the Li+ ion diffusion coefficient or Na+ diffusion coefficient of the spent cathodes;
• wherein the hydrogen bond donors possess functional groups with active hydrogen atom showing positive charge, or the capability of terminal positive charge from molecular polarity or ionization;
• wherein the hydrogen bond acceptors possess functional groups with active atom showing negative charge, a π-system, or other negative charge-concentrated sites induced by molecular internal polarity;
• and
• wherein the hydrogen bond donors or hydrogen bond acceptors provide capability of reduction and element replenishment capability for spent cathodes with battery capacities of lower than 80% of the original values.